<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* 4. 复合选择器 */
        /* li {
            color: red;
        }
        a {
            color: red;
        } */
        /* li a {
            color: red;
        } */
        /* #middle li {
            color: red;
        } */
         /* ul li a {
            color: green;
         }
         ol li a {
            color: pink;
         } */
        /* #a1, #a2 {
            color: pink;
        } */
        /* ul>li>a {
            color: red;
        } */

        /* 5. 通配符选择器 */
        /* * {
            color: green;
            font-size: 40px;
        } */

        .font32 {
            /* border-style: solid;
            border-width: 2px;
            border-color: red; */
             border: solid 2px red;
             height: 100px;
             width: 500px;
        }

        span {
            display: block;
            border: 2px solid red;
            height: 100px;
            width: 500px;
        }
        
    </style>
</head>
<body>
    <div class="font32">我是一个div, class为font32</div>
    <div class="font32">我是一个div, class为font32</div>
    <div><a href="#">我是一个div</a></div>
    <ul>
        <li>aaa</li>
        <li>bbb</li>
        <li><a href="#" id="a1">ccc</a></li>
    </ul>
    <ol id="middle">
        <li>1111</li>
        <li>2222</li>
        <li>3333</li>
    </ol>
    <ol>
        <li>1111</li>
        <li>2222</li>
        <li><a href="#" id="a2">3333</a></li>
    </ol>
    <button id="submit">提交</button>
    <span>span标签</span>
</body>
</html>